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Health Department has requested that the flow rate be calculated as 140 gallons per <br />bedroom per day to reflect maximum usage. On March 4, 2020, however, Michael Kith <br />of the San Joaquin County Environmental Health Department dictated a new procedure <br />for calculating residential flow, developed in consultation with Norman Hantzsche <br />(author of the 1992 paper discussed previously). He indicated that wastewater flow <br />from a single-family residence should be calculated as 100 gallons per day (gpd) for the <br />first bedroom and 50 gpd for each additional bedroom; additional residences should be <br />calculated in the same manner (personal communication, March 4, 2020). <br />Using this method, the existing two-bedroom home will contribute an estimated average <br />daily flow of 150 gpd. <br />A typical residential concentration of 35 mg/L of nitrate as N was selected for the <br />proposed residence (Crites and Tchobanoglous, 1998). <br />Crites and Tchobanoglous indicate that 5 gallons per day per user is typical for a public <br />lavatory. This value is selected to represent use of the shop restroom. The nitrate as <br />nitrogen (N) concentration of the shop restroom use is estimated to be 85 mg/L (US <br />EPA, 1980) because no diluting fixtures such as washing machines or showers are <br />included in the flow. <br />For Parcel 1, the maximum average daily flow for the Site was estimated to be 150.7 <br />gallons per day (gpd). Through the use of a weighted average, the average <br />concentration of the different effluent flows and concentrations was determined to be <br />35.2 mg/L-N at 150.7 gallons per day. Please see the following tables: <br />Table 4. Average Daily Flow Calculation, Parcel 1 <br />Use Units Rate Subtotal Reduction Average Daily <br />Flow <br />Residence 2 bed 150 gal/2BR/day 150 gpd None 150 gpd <br />rooms <br />Shop Restroom 1 5 gal/person/day 5 gpd 1/7 0.7 gpd <br />Total 150.7 gpd <br />Reduction factors convert calculated flow into average daily flow over a year. The factor 1/7 refers to days per week. <br />No reduction is used for a residence since it is continuously occupied. <br />LOGE 2150 Page 12 <br />